Cobalt restate and method of



Patented Nov. 18, 1947 COBALT RESINATE AND METHOD OF PRODUCING Paul R. Mosher, Wilmington, Del., assignor to Hercules Powder Company, Wilmington, Del., a corporation of Delaware No Drawing. Application September Serial No. 409,534

12 Claims. (Cl. 260-105) This invention relates to the production of cobalt resinates and more particularly to fused cobalt resinates of improved characteristics and to the method of production thereof.

By reaction of wood or gum rosins with suitable cobalt compounds, cobalt resinates have been prepared Containing an amount of cobalt in combined form up to the theoretical cobalt content of the neutral diresinate. Production of the cobalt resinates from such rosins has been carried out either by fusion of the rosin With suitable cobalt compounds or by a double decomposition procedure involving treatment of a water-soluble salt of the rosin with a soluble cobalt salt. By the precipitation method cobalt resinates containing up to the theoretical cobalt content for the neutral diresinate have been prepared. By the fusion method, on the other hand, it has been impossible to introduce more than a small amount of cobalt due to the fact that the fusion mixture sets to a solid mass or blocks, and consequently only acid resinates of low cobalt content have been capable of production by the fusion method. The blocking phenomenon encountered is the result of a change of the fluid mix into a solid, non-homogeneous, partially crystallized, opaque and relatively insoluble mass.

It is an object of this invention to provide balt resinates of higher cobalt content than has heretofore been possible.

It is another object to provide fused cobalt resinates of high cobalt content which posses many improved characteristics.

It is a further object to provide a method of producing fused cobalt resinates of high metal content.

Other objects of the invention will appear hereinafter.

The above objects may be accomplished in ac- I cordance with this invention by fusing a cobalt compound capable of reaction with rosin, at a temperature in the range of about 200 C. to about 340 C. with a rosin which has been previously subjected to a heat treatment at a temperature in the range of about 250 C. to about 350 C. until the optical rotation of the rosin in the solid state has reached the range of about +20 to about +60 and preferably from about +30 to about +50. It has been found in accordance with this invention that by first subjecting rosin to a heat treatment to increase its optical rotation to at least +20 and then fusing with a reactive cobalt compound at the above temperatures all blocking difiiculties are avoid ed and resinates having a cobalt content above the theoretical cobalt content of the cobalt diresinate are readily obtained. Thus, in accordance with this invention, cobalt resinates having a cobalt content greater than the equivalent combining proportion of the rosin based on its acidity and as high as 19% by weight are provided by fusing the heat-treated rosin with a suflicient amount of a reactive cobalt compound to give the required combining proportion of cobalt. The theoretical cobalt content of a diresinatc prepared from a rosin of theoretical acid number is 8.93%. This amount of cobalt thus represents the maximum obtainable in a resinateby the precipitation method and far exceeds the amount capable of introduction by a fusion procedure.

In carrying out the process of the invention a heat-treated rosin having a specific optical rotation from about +20 to about and preferably from about +30 to about +50 is reacted with a cobalt compound capable of reaction therewith to provide a salt. Such a compound may be a basic cobalt compound or it may be a cobalt salt of a volatile weak acid, or any other cobalt compound which under the fusion conditions liberates its cobalt. Suitable cobalt compounds are, for example, cobalt acetate, cobalt formate, cobalt lactate, cobalt butyrate, cobalt oxide, mixtures of cobalt oxide with a fatty acid cobalt salt as the acetate, mixtures ofcobalt oxide with a fatty acid as acetic acid, etc. In using cobalt oxide it is usually desirable to employ'it in admixturewith a fatty acid salt or a fatty acid since the reactivity of the oxide alone in some cases is not sufiicient to provide homogeneous resinates. If desired, a small amount of calcium acetate or other fatty acid salt of calcium or a fatty acid salt of zinc, lead, manganese, etc., may be employed with cobalt oxide to facilitate reaction of thelatter. When such auxiliary agents are used, they combine partially with the heat-treated rosin also. The amount of such auxiliary agent necessary will only be a small amount, as for example from about 0.5% to about 2% by weight based on the rosin.

The fusion reaction of the invention is performed by heating the heat-treated rosin of the above characteristics to a temperature in the range of about 200 C. toabout 340 C. and adding the cobalt compound either gradually or at one time, preferably while agitating the mixture. Foaming accompanies" the reaction and agitation serves to hold the foaming to a minimum. The foaming is more severe at the lower temperatures and the reaction is also slower. At temperatures above about 320 C. the reaction is vigorous but the yield becomes diminished due to volatilization of light ends from the heat-treated rosin. Preferable temperatures for the reaction therefore are from about 230 C. to about 320 C.

The time of reaction required to form the novel resinates is dependent on the temperature employed, the particular cobalt compound used, the degree of agitation and the amount of metal being introduced, as well as on other factors. Thus, the reaction time may be varied'from about minutes to several hours. Presence of an inert atmosphere, such as may be provided by carbon dioxide, nitrogen, etc., prevents oxidation of the heat-treated rosin and the resinate at the elevated temperature employed and is therefore desirable, though not essential.

The heat-treated rosin which has been found to be useful in carrying out this invention may be obtained by methods well known in the art. It has been recognized that heating of a natural rosin, as wood or gum rosin, at temperatures of 250 C. to 350 C. brings about both chemical and physical transformations in therosin. The heat treatment has been carried out both in the presence and absence of an inert atmosphere and the same fundamental changes appear to occur. The specific optical rotation increases in the positive direction as the heat treatment progresses. The crystallizing tendencies of the rosin alsodecrease and the rosin becomes bleached in color as the heat treatment is prolonged. It is not known which of these chemical and physical changes is responsible for the different behavior of the rosin in the production of cobalt resinate by the fusion method. It is probably a combination of each of the transformations which provides such a pro nounced effect in resinate formation. v The most accurate meansof defining the heattreated rosinswhich possess the necessary characteristics for practice of this invention is by means of the specific optical rotation, as measured on the solid rosin. Thus, it has been found that when the opticalrotation of the heat-treated rosin, as measured on the'solid rosin, reaches +20 the characteristic of forming cobalt resinates of high cobalt content by a fusion process without blocking "is 'first observed. This characteristic is most pronounced when the heat treatment has been sufficient to raise the optical rotation to +30. When the optical rotation is above +30 the heat-treated rosin will be substantially non-crystalline and non-crystallizing. It will also be substantially lighter in color than the rosin' from which it was produced, thereby providing an improvement in the color of the resinate. The heating time required to provide the desired changes in'the rosin will vary with the particular temperature employed, It may be from about five minutes to as long as 8 hours,

The novel cobalt resinates described in accordance with this invention will be sharply differentiated from prior art cobalt resinates in their higher cobalt contents. They will thus be more desirable in the various uses of cobalt resinates, as in driers for paints and varnishes, in printing inks, etc. They will be clear, homogeneous and substantially neutral resins having a deep purple color.

The following specific examples illustrate the various embodiments of the invention:

Example I A heat-treated wood rosin was prepared by subjecting N wood rosin to a temperature of 310 to 315 C. until its optical rotation reached +40. The heat-treated rosin so obtained had an acid number of 133 and a melting point (drop) of 74 C. Sixty-nine parts by weight of the heat-treated rosin were melted and heated to a temperature of 220 C. Thirty-seven parts by weight of cobalt acetate were added to the molten rosin in small portions at a time with continuous agitation, allowing time between each addition for the reaction to become complete, as evidenced by the subsiding of foaming and evolution of acetic acid. The temperature was raised gradually during the addition to a maximum of 250 C. The total time of addition was 20 minutes, after which the resinate was cooled. The cooled cobalt resinate was a clear, homogeneous resin of purple color having a drop melting point of 137 C. and a cobalt content of 11 Example '11 One hundred parts by Weight of the heattreated wood rosin used in Example I were melted and heated to a-temperature of 270 C. One hundred parts by weight of cobalt acetate were then added in small portions at a time with agitation, allowing time for the reaction to become complete between each addition. The temperature was raised gradually to 305 C. during the addition, which required 50 minutes. The cooled cobalt resinate obtained was a clear, homogeneous, resinous solid of purple color having a cobalt content of 19% and a melting point (drop) of C.

Example III A heat-treated gum rosin was prepared by subjecting WW gum rosin to a heat treatment at a temperature of 310 to 315 C. until theoptical rotation reached +41. The heat-treated rosin so obtained had an acid number of 127 and a melting point (drop) of 825 C. One hundred parts by weight of the heat-treated gum rosin were melted and heated to a temperature of 240 C. Eighty-six parts by weight of cobalt acetate were then added in small portions at a time with agitation, allowing the reaction to become complete between each addition. The temperature was raised gradually during the addition to a maximum of 330 C. The total time of addition was 35 minutes. The cobalt resinate obtained after cooling was a clear homogeneous rosin-like product having a cobalt content of 17% and a melting point (drop) of 163 C.

Thus it will be apparent from the above description and illustrative examples that by means of this invention a process is provided for obtaining cobalt resinates of higher metal content than heretofore possible. The process itself provides an important advance in the art of preparation of cobalt resinates. By means of the improved process all blocking difficulties formerly encountered in preparation of cobalt resinates by a fusion process have been overcome, andfused cobalt resinates of greater utility due to their higher metal content are made available.

Itwill be understood that the details and examples hereinbefore set forth are illustrative only and that the invention as herein broadly described and claimed is in no way limited thereby.

What I claim and desire to protect by Letters Patent is:

1. A cobalt resinate of a heat-treated rosin, said resinate having a cobalt content greater than the equivalent combining proportion of the rosin based on its acidity but not in excess of about 19% by weight, said heat-treated rosin being the product obtained by a process consisting of heating a natural rosin to a temperature in the range of about 250 C. to about 350 C. until the specific optical rotation has reached the range of about +20 to about +60.

2. A cobalt resinate of a heat-treated rosin, said resinate having a cobalt content greater than the equivalent combining proportion of the rosin based on its acidity but not in excess of about 19% by weight, said heat-treated rosin being the product obtained by a process consisting of heating a natural rosin to a temperature in the range of about 250 C. to about 350 C. until the specific optical rotation has reached the range of about +30 to about +50", v

3. A cobalt resinate of a heat-treated rosin, said resinate having a cobalt content reater than the equivalent combining proportion of the rosin based on its acidity but not in excess of about 19% by weight, said heat-treated rosin being the product obtained by a process consisting of heating a wood rosin to a temperature in the range of about 250 C. to about 350 C. until the specific optical rotation has reached the range of about +20 to about +60.

4. A cobalt resinate of a heat-treated rosin, said resinate having a cobalt content greater than the equivalent combining proportion of the rosin based on its acidity but not in excess of about 19% by weight, said heat-treated rosin being the product obtained by a process consisting of heating a gum rosin to a temperature in the range of about 250 C. to about 350 C. until the specific optical rotation has reached the range of about +20 to a out +60.

5. A cobalt resinate of a heat-treated rosin, said resinate having a cobalt content greater than the equivalent combining proportion of the rosin based on its acidity but not in excess of about 19% by weight, said heat-treated rosin being the product obtained by a process consisting of heating a wood rosin to a temperature in the range of about 250 C. to about 350 C. until the specific optical rotation has reached the range of about +30 to about +50.

6. A cobalt resinate of a. heat-treated rosin, said resinate having a cobalt content greater than the equivalent combining proportion of the rosin based on its acidity but not in excess of about 19% by Weight, said heat-treated rosin being the product obtained by a process consisting of heating a gum rosin to a temperature in the range of about 250 C. to about 350 C. until the specific optical rotation has reached the range of about +30 to about +50.

'7. The method of producing a cobalt resinate of a heat-treated rosin, said resinate having a cobalt content greater than the equivalent combining proportion of the rosin based on its acidity but not in excess of about 19% by Weight, which comprises fusing a heat-treated rosin with a cobalt compound capable of reaction with the rosin, in an amount sufficient to give a resinate of the above-defined cobalt content at a temperature within the range of about 200 C. to about 340 C., said heat-treated rosin being the product obtained by a process consisting of heating a natural rosin at a temperature in the range of about 250 C, to about 350 C. until the specific optical rotation has reached the range of about +20 to about +60.

8. The method of producing a cobalt resinate of a heat-treated rosin, said resinate having a cobalt content greater than the equivalent combining proportion of the rosin based on its acidity but not-in e'xcessof about/19% by'Weig'ht, which comprises fusing a heat-treated rosin with a cobalt compound capable of reaction with the rosin, in an amount sufficient to give a resinate of the above-defined cobalt content at a temperature withinthe range of about 230 C. to about 320 C., said heat-treated rosin being the product obtained by a process consisting of heating a natural rosin at a temperature in the range of about 250 C. to about 350 C. until the optical rotation :has reached the range -.of about +20 to about +60.

9. The method of producing a cobalt resinate of a heat-treated rosin, said resinate having a cobalt content greater than the equivalent combining proportion of the rosin based on its acidity but not in excess of about 19% by weight, which comprises fusing a heat-treated rosin with a cobalt compound capable of reaction with the rosin, in an amount sufficient to give a resinate of the above-defined cobalt content at a temperature within the range of about 200 C. to about 340 0., said heat-treated rosin being the product obtained by a process consisting of heating a natural rosin at a temperature in the range of about 250 C. to about 350 C. until the specific optical rotation has reached the range of about +30 to about +50.

10. The method of producing a cobalt resinate of a heat-treated rosin, said resinate having a cobalt content greater than the equivalent combining proportion of the rosin based on its acidity but not in excess of about 19% by weight, which comprises fusing a heat-treated rosin with cobalt acetate in an amount sufficient to give a resinate of the above-defined cobalt content at a temperature within the range of about 200 C. to about 340 C., said heat-treated rosin .being the product obtained by a process consisting of heating a natural rosin at a temperature in the range of about 250 C. to about 350 C. until the specific optical rotation has reached the range of about +20 to about +60.

11. The method of producing a cobalt resinate of a heat-treated rosin, said resinate having a cobalt content greater than the equivalent combining proportion of the rosin based on its acidity but not in excess of about 19% by weight, which comprises fusing a heat-treated rosin with a mixture of cobalt oxide and cobalt acetate in an amount suflicient to give a resinate of the abovedefined cobalt content at a temperature within the range of about 200 C. to about 340 C., said heat-treated rosin being the product obtained by a process consisting of heating a natural rosin at a temperature in the range of about 250 C. to about 350 C. until the specific optical rotation has reached the range of about +20 to about +60.

12. The method of producing a cobalt resinate of a heat-treated rosin, said resinate having a cobalt content greater than the equivalent combining proportion of the rosin based on its acidity but not in excess of about 19% by weight, which comprises fusing a heat-treated rosin with a cobalt compound capable of reaction with the rosin, in an amount sufiicient to give a resinate of the above-defined cobalt content and in the presence of a small amount of calcium acetate as catalyst at a temperature within the range of about 200 C. to about 340 C., said heattreated rosin being the product obtained by a process consisting of heating a natural rosin at a temperature in the range of about 250 C. to

"I about 350 C. until the specific optical rotation 7' 8 has reached therange ofabout +20 to' about Number Name Date +60 2,205,458 Pragofi June 3, 1942 PAUL R. MOSHER. 2,225,246 Hasselstrom Dec. 17, 1940 2,241,341 Ender May 6, 1941 REFERENCES CITED 5 2,247,399 Palmer et a1. (1) July 1, 1941 2346 993 Palmeret a1 (2) Apr. 18, 1944 T f f Y me erences are m 2,346,994 Palmer et a1. (3) Apr. 13, 1944 7 UNITED STATES PATENTS V I OTHER REFERENCES Number Name 1 Date m Ruzicka, Helvetica. Chimica, Acta, vol. 5, 1922,

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